Split-gate MOSFET

• Main Authors: Su Jiong-Guang, Liu Chih-Cheng, Chou Hung-Wen
• Format: Patent
• Language: English
• Published: 07.11.2017
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

A split-gate MOSFET includes first and second epitaxial layers, first, second, and third gates, a gate oxide layer, a trench oxide layer, and a trench implantation region formed on a substrate in order. The second epitaxial layer has a doping concentration greater than that of the first epitaxial layer. A plurality of trenches is in the first and second epitaxial layers. Both the first and second gates are located in each of the trenches in a cell region. The third gates are located in each of the trenches in a terminal region. The third gate closest to the cell region is grounded, and the others are floating. The gate oxide layer is disposed between the first and second gates. The trench oxide layer is located between the first gate and the first epitaxial layer and located between the trench surface and the third gate. The trench implantation region is located in the first epitaxial layer at the bottom of the trench and has a doping concentration less than that of the first epitaxial layer.